The vast majority of currently manufactured vehicles include a cruise control system that enables a driver to maintain a set speed without manual adjustment of the throttle or brake pedals. The cruise control system is generally reactive by nature. In particular, upon recognition of a speed error, the cruise control system attempts to correct for the speed error by increasing or decreasing the throttle. Since the cruise control system is unable to predict an increase or decrease in loading, it must react to variations from the desired speed and adjust the throttle accordingly. This reactive nature creates a system latency, i.e., a delay in adjusting the throttle to changes in loading. The system latency results in a larger response to the recognized speed error, which diminishes fuel economy. In addition, when traveling on a significant decline, such as going down a hill, the vehicle may accelerate past the set speed due to the pull of gravity. This accelerated speed can require the driver to intervene, such as by applying the brake. Similarly, when traveling on a significant incline, such as going up a hill, the vehicle typically drops below the set speed, increases the throttle to get back to the set speed, but then accelerates past the set speed at the top of the hill, creating another non-optimum condition.